diff options
Diffstat (limited to 'kernel/posix-cpu-timers.c')
| -rw-r--r-- | kernel/posix-cpu-timers.c | 48 |
1 files changed, 21 insertions, 27 deletions
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 00bb252f29a..f66bdd33a6c 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -232,31 +232,24 @@ static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p, void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times) { - struct sighand_struct *sighand; - struct signal_struct *sig; + struct signal_struct *sig = tsk->signal; struct task_struct *t; - *times = INIT_CPUTIME; + times->utime = sig->utime; + times->stime = sig->stime; + times->sum_exec_runtime = sig->sum_sched_runtime; rcu_read_lock(); - sighand = rcu_dereference(tsk->sighand); - if (!sighand) + /* make sure we can trust tsk->thread_group list */ + if (!likely(pid_alive(tsk))) goto out; - sig = tsk->signal; - t = tsk; do { times->utime = cputime_add(times->utime, t->utime); times->stime = cputime_add(times->stime, t->stime); times->sum_exec_runtime += t->se.sum_exec_runtime; - - t = next_thread(t); - } while (t != tsk); - - times->utime = cputime_add(times->utime, sig->utime); - times->stime = cputime_add(times->stime, sig->stime); - times->sum_exec_runtime += sig->sum_sched_runtime; + } while_each_thread(tsk, t); out: rcu_read_unlock(); } @@ -363,7 +356,7 @@ int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp) } } else { read_lock(&tasklist_lock); - if (thread_group_leader(p) && p->signal) { + if (thread_group_leader(p) && p->sighand) { error = cpu_clock_sample_group(which_clock, p, &rtn); @@ -439,7 +432,7 @@ int posix_cpu_timer_del(struct k_itimer *timer) if (likely(p != NULL)) { read_lock(&tasklist_lock); - if (unlikely(p->signal == NULL)) { + if (unlikely(p->sighand == NULL)) { /* * We raced with the reaping of the task. * The deletion should have cleared us off the list. @@ -691,10 +684,10 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, read_lock(&tasklist_lock); /* * We need the tasklist_lock to protect against reaping that - * clears p->signal. If p has just been reaped, we can no + * clears p->sighand. If p has just been reaped, we can no * longer get any information about it at all. */ - if (unlikely(p->signal == NULL)) { + if (unlikely(p->sighand == NULL)) { read_unlock(&tasklist_lock); put_task_struct(p); timer->it.cpu.task = NULL; @@ -863,7 +856,7 @@ void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp) clear_dead = p->exit_state; } else { read_lock(&tasklist_lock); - if (unlikely(p->signal == NULL)) { + if (unlikely(p->sighand == NULL)) { /* * The process has been reaped. * We can't even collect a sample any more. @@ -1199,7 +1192,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer) spin_lock(&p->sighand->siglock); } else { read_lock(&tasklist_lock); - if (unlikely(p->signal == NULL)) { + if (unlikely(p->sighand == NULL)) { /* * The process has been reaped. * We can't even collect a sample any more. @@ -1279,10 +1272,6 @@ static inline int fastpath_timer_check(struct task_struct *tsk) { struct signal_struct *sig; - /* tsk == current, ensure it is safe to use ->signal/sighand */ - if (unlikely(tsk->exit_state)) - return 0; - if (!task_cputime_zero(&tsk->cputime_expires)) { struct task_cputime task_sample = { .utime = tsk->utime, @@ -1298,7 +1287,10 @@ static inline int fastpath_timer_check(struct task_struct *tsk) if (sig->cputimer.running) { struct task_cputime group_sample; - thread_group_cputimer(tsk, &group_sample); + spin_lock(&sig->cputimer.lock); + group_sample = sig->cputimer.cputime; + spin_unlock(&sig->cputimer.lock); + if (task_cputime_expired(&group_sample, &sig->cputime_expires)) return 1; } @@ -1315,6 +1307,7 @@ void run_posix_cpu_timers(struct task_struct *tsk) { LIST_HEAD(firing); struct k_itimer *timer, *next; + unsigned long flags; BUG_ON(!irqs_disabled()); @@ -1325,7 +1318,8 @@ void run_posix_cpu_timers(struct task_struct *tsk) if (!fastpath_timer_check(tsk)) return; - spin_lock(&tsk->sighand->siglock); + if (!lock_task_sighand(tsk, &flags)) + return; /* * Here we take off tsk->signal->cpu_timers[N] and * tsk->cpu_timers[N] all the timers that are firing, and @@ -1347,7 +1341,7 @@ void run_posix_cpu_timers(struct task_struct *tsk) * that gets the timer lock before we do will give it up and * spin until we've taken care of that timer below. */ - spin_unlock(&tsk->sighand->siglock); + unlock_task_sighand(tsk, &flags); /* * Now that all the timers on our list have the firing flag, |